Window fan



FIG. 1 is a top perspective view of a window fan showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a top elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a left side elevation view thereof; and,

FIG. 6 is a bottom elevation view thereof. 

The ornamental design for a window fan, as shown. 